From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 305EEECE58C for ; Wed, 9 Oct 2019 18:12:26 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 05B7C20679 for ; Wed, 9 Oct 2019 18:12:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 05B7C20679 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:53616 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIGRk-0008UO-LJ for qemu-devel@archiver.kernel.org; Wed, 09 Oct 2019 14:12:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55837) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iI924-0000ux-8l for qemu-devel@nongnu.org; Wed, 09 Oct 2019 06:17:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iI920-0006r7-Iu for qemu-devel@nongnu.org; Wed, 09 Oct 2019 06:17:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44204) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iI920-0006qv-Ak for qemu-devel@nongnu.org; Wed, 09 Oct 2019 06:17:20 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7FD08306081C; Wed, 9 Oct 2019 10:17:19 +0000 (UTC) Received: from work-vm (ovpn-117-215.ams2.redhat.com [10.36.117.215]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8C8565C1D6; Wed, 9 Oct 2019 10:17:18 +0000 (UTC) Date: Wed, 9 Oct 2019 11:17:16 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang Subject: Re: [PATCH 3/3] migration/postcopy: replace have_listen_thread check with PostcopyState check Message-ID: <20191009101716.GH2893@work-vm> References: <20191006000249.29926-1-richardw.yang@linux.intel.com> <20191006000249.29926-4-richardw.yang@linux.intel.com> <20191008191551.GN3441@work-vm> <20191009013733.GF26203@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191009013733.GF26203@richard> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Wed, 09 Oct 2019 10:17:19 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > On Tue, Oct 08, 2019 at 08:15:51PM +0100, Dr. David Alan Gilbert wrote: > >* Wei Yang (richardw.yang@linux.intel.com) wrote: > >> After previous cleanup, postcopy thread is running only when > >> PostcopyState is LISTENNING or RUNNING. This means it is not necessary > >> to spare a variable have_listen_thread to represent the state. > >> > >> Replace the check on have_listen_thread with PostcopyState and remove > >> the variable. > >> > >> Signed-off-by: Wei Yang > >> --- > >> migration/migration.h | 1 - > >> migration/ram.c | 2 +- > >> migration/ram.h | 1 + > >> migration/savevm.c | 4 +--- > >> 4 files changed, 3 insertions(+), 5 deletions(-) > >> > >> diff --git a/migration/migration.h b/migration/migration.h > >> index 4f2fe193dc..a4d639663d 100644 > >> --- a/migration/migration.h > >> +++ b/migration/migration.h > >> @@ -63,7 +63,6 @@ struct MigrationIncomingState { > >> /* Set this when we want the fault thread to quit */ > >> bool fault_thread_quit; > >> > >> - bool have_listen_thread; > >> QemuThread listen_thread; > >> QemuSemaphore listen_thread_sem; > >> > >> diff --git a/migration/ram.c b/migration/ram.c > >> index 769d3f6454..dfc50d57d5 100644 > >> --- a/migration/ram.c > >> +++ b/migration/ram.c > >> @@ -4188,7 +4188,7 @@ static bool postcopy_is_advised(void) > >> return ps >= POSTCOPY_INCOMING_ADVISE && ps < POSTCOPY_INCOMING_END; > >> } > >> > >> -static bool postcopy_is_running(void) > >> +bool postcopy_is_running(void) > >> { > >> PostcopyState ps = postcopy_state_get(); > >> return ps >= POSTCOPY_INCOMING_LISTENING && ps < POSTCOPY_INCOMING_END; > >> diff --git a/migration/ram.h b/migration/ram.h > >> index bd0eee79b6..44fe4753ad 100644 > >> --- a/migration/ram.h > >> +++ b/migration/ram.h > >> @@ -59,6 +59,7 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms); > >> /* For incoming postcopy discard */ > >> int ram_discard_range(const char *block_name, uint64_t start, size_t length); > >> int ram_postcopy_incoming_init(MigrationIncomingState *mis); > >> +bool postcopy_is_running(void); > >> > >> void ram_handle_compressed(void *host, uint8_t ch, uint64_t size); > >> > >> diff --git a/migration/savevm.c b/migration/savevm.c > >> index dcad8897a3..2a0e0b94df 100644 > >> --- a/migration/savevm.c > >> +++ b/migration/savevm.c > >> @@ -1836,7 +1836,6 @@ static void *postcopy_ram_listen_thread(void *opaque) > >> qemu_loadvm_state_cleanup(); > >> > >> rcu_unregister_thread(); > >> - mis->have_listen_thread = false; > >> postcopy_state_set(POSTCOPY_INCOMING_END, NULL); > > > >That now needs a big comment saying it must be the last thing in the > >thread, because now it's got meaning that it's here. > > > >> > >> return NULL; > >> @@ -1880,7 +1879,6 @@ static int loadvm_postcopy_handle_listen(MigrationIncomingState *mis) > >> return -1; > >> } > >> > >> - mis->have_listen_thread = true; > >> /* Start up the listening thread and wait for it to signal ready */ > >> qemu_sem_init(&mis->listen_thread_sem, 0); > >> qemu_thread_create(&mis->listen_thread, "postcopy/listen", > >> @@ -2518,7 +2516,7 @@ int qemu_loadvm_state(QEMUFile *f) > >> > >> trace_qemu_loadvm_state_post_main(ret); > >> > >> - if (mis->have_listen_thread) { > >> + if (postcopy_is_running()) { > >> /* Listen thread still going, can't clean up yet */ > >> return ret; > >> } > > > >Can you explain to me why this is afe in the case of a failure in > >loadvm_postcopy_handle_listen between the start where it sets > >the state to LISTENING, and the point where it currently sets > >hasve_listen_thread ? Wouldn't this cause qemu_loadvm_state > >not to cleanup? > > > > I have to say you are right. listen_thread may not started when PostcopyState > is already set to LISTENING. > > The ugly fix may be set PostcopyState back to original one. Not sure whether > you would like this. I think the 'have_listen_thread' might be the simplest solution though; it's very simple! Dave > >Dave > > > >> -- > >> 2.17.1 > >> > >-- > >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > -- > Wei Yang > Help you, Help me -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK